Enhanced resin-modified glass-ionomers

Table 8 Physical properties of enhanced resin-modified glass-ionomers (Activa restorative and Activa Base/Liner) [30]...

As with glass-ionomer cements, flnoride release from polyacid-modified composite resins is snstained for long periods of time [23] and is enhanced by placing the polyacid-modified composite resin in acidic storage media [25,36]. This property has been snggested to be beneficial in the case of resin-modified glass-ionomers [37], since it wonld lead to enhanced release of protective fluoride ion under the very conditions that promote dental caries. A similar argnment can be advanced for polyacid-modified composite resins, and it may be that this ability to release extra fluoride under conditions of low pH is beneficial clinically. 

Enhanced performance resin-modified glass-ionomer cement... 

Composition of enhanced performance resin-modified glass-ionomers... 

The resin-modified type is described in this chapter as enhanced performance resin-modified glass-ionomers. These are available as a restorative and liner/base grades. 

The enhanced performance resin-modified glass-ionomers are high in resin, and as a result appear to have somewhat compromised adhesion. Their bioactivity appears very good. Considerable further work is required to know whether or not these materials represent a significant advance in glass-ionomer technology and restorative dentistry. 

The essential features of the two basic types of restorative material are given in Table 2.1. From this, it can be seen that each type has its own advantages and disadvantages. In terms of overall properties, modem composite resins appear to be favoured, and there is evidence that these materials are the ones used in the majority of aesthetic repairs in dentistry, particularly in adults. However, as the development of the polyacid-modified composite resins (compomers) shows, these materials are far from perfect, and there is unquestionably scope to enhance their properties. Glass-ionomer cements have properties that would seem to indicate the direction in which improvements could be made, despite the technical difficulties in doing so. 

There are two types of enhanced property glass-ionomers, one of each type (conventional and resin-modified). 

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